Automatic stepless transmission



May l5, 1951 R. H. BAILEY 2,553,126

AUTOMATIC sTEPLEss TRANSMISSION Filed July 16, 1947 2 sh'eets-sxeet 1www i /////////I/ll| I l I II\\\\\\I\\\\\\\\\; IHIHIIl|||||||IlIlIIIIIIIIIIIIIIIIIIIIIIH IHIIIIHIIIIIIIIHIHI II #El\T\\\\\ May 15, 1951 R. H. BAILEY 'AUTOMATIC sTEPLEss TRANSMISSION 2Sheets-Sheet 2 Fled'July 16, 1947 n.. M... .U m5

Nb @u N MN f. D Q A A@ NN.. QN, MVN f @NN Patented May 15, 1951 UNITEDSTATES PATENT OFFICE.

Claims. l

This invention relates to transmissions which can be used as asubstitute for the conventional clutch of the modern automobile and atthe same time as a substitute for the three or four speed transmission.The invention, however, is noi'l limited to the use in connection withautomobiles or with internal combustion engines. It may be used inconnection with any prime mover whose power is to be smoothlytransmitted through a number of speed ratios from the driving to thedriven shaft without interruption.

It is an object of the invention to provide a transmission which iscapable of an unlimited combination of power-to-speed ratios withoutinterruption in the tractive force or in the trans- E mission of thepower from the driving to the driven shaft. A related object is toaccomplish such variation in gear ratio smoothly and automatically tomeet varying power demands and driving conditions.

One of the advantages of the invention is that the transmission can beshifted from forward to reverse or vice versa from any speed without anyunmeshing of gears. Another advantage is that the transmission enablesthe engine to be used as a power brake when desired.

Along with the above mentioned advantages, the transmission has thefurther advantage that a dead car can be started by being pushed, as

with conventional transmissions. At the same ,f

time a direct coupling between the engine and wheels or between thedriving and driven shaft is maintained when the car is parked with theengine off. According to the invention only a three-position manualselector lever movable into forward, neutral and reverse positions isrequired.

In addition to the foregoing a linger operated brake to supplement thefoot brake for parking may be operated `without the necessity of theapplication of any measurable force as compared with the ordinary brakesnow commonly used on the modern automobile.

Other objects and advantages of the invention will become apparent as itis described in the accompanying drawings.

In the drawings:

Fig. 1 is an exploded View of the gear members employed in theinvention;

Fig. 2 is a View of the gear members illustrated in Fig. l, but inassembled condition; Fig. 2 is partly broken away for clearillustration;

Fig. 3 is a diagrammatic illustration of the control apparatus employedin combination with the gearing mechanism illustrated in Figs. l and 2;and

Fig. 4 is a diagrammatic illustration of a poppet type selector valvewhich may be used in the control apparatus of the invention.

Referring particularly to Fig. 1 of the drawings, there is shown indiagrammatic form a driving shaft |00 which may be coupled in anyconventional fashion with a gasoline engine, a Diesel engine or anyother sort of engine or motor which may require a transmission mechanismto transmit the power from the driving shaft to a driven shaft. Theinvention will be described as if embodied in an automobile, but itsho-uld be understood that the invention is not so limited.

Although spur gears are illustrated and referred to in the followingdescription it will be understood that spiraled, beveled or any othercommon gear forms may be used.

On the driving shaft |00 is a spur gear |02. The gear |02 meshes with amuch larger spur gear |04 on the periphery of a cylindrical member ordrum |06 which is thus driven by the gear |02 when the driving shaftrotates. At one edge of the member |06 are formed bevel gear teeth |08which may mesh with the small bevel gears Illia, Hb. The gears ||0a and||0b are formed integral with or mounted upon stud shafts ||2 which aremounted in and rotate within the arms H4 of a U-shaped yoke H5. The yoke5 is mounted upon and turns with a shaft H6. As will hereinafter appear,the shaft H6 controls the reverse rotation of the transmission.

In axial alignment with the shaft ||6 is a similar shaft |20 having abevel gear |22 on the edge thereof. The shaft |20 is coaxial also withgears |04 and I 03 and the shaft |20 may pass through the center of themember It. Meshing with the bevel gear |22 are bevel gears |246: and|241) which are mounted upon the opposite ends of the shafts ||2 fromthe bevel gears ||0a and H01) and on opposite sides of the yoke arms H4.

Coaxial with the shaft Ils is a gear |38 similar to the gear |08 on acylindrical drum member |36 similar to the member |00. Also a large spurgear I 34 similar to the gear |04 is formed on the member |30. The gear|34 meshes with a spur gear or pinion |32 mounted upon a driven shaft130, which may drive the wheels of an auto, directly or throughconventional differential or other gearing: Or any other mechanism maybe driven.

If the driving shaft |00 is rotating at a constant speed in onedirection it will drive the gears |04 and ma also at a constant butslower speed.

The neutral condition- As in the neutral condition of a common autotransmission with the auto stationary, the driving shaft is rotating inone direction at a constant speed, while the driven shaft is stationary.With this condition of the driving and driven shafts the forward controlshaft |20 will rotate freely in the same direction as driving gear |04but at a greater speed; the

3 reverse control shaft I6 will rotate freely in the same direction asdriving gear |04 but at a less speed than the driving gear.

Retardation of the above mentioned free rotation of either the forwardcontrol shaft l2@ or of the reverse control shaft I6, selectivelydetermines whether the auto will move forward or backward.

The forward condition-When the forward control shaft |20 is slowed downto the same speed as the driving gear |04, the driven gear |34 and thereverse control shaft will be driven by a direct drive at the same speedand in the same direction as the driving gear |04.

If the forward control shaft |20 is slowed down somewhat but not so slowas the driving gear |04, the driven gear |30 will rotate in the samedirection but Vat less speed than the driving gear; As the rotation ofthe forward control shaft decreases, the speed of rotation of thereverse control shaft will increase.

If the forward control shaft |20 is slowed down to a speed less than thedriving gear or is'stopped, the driven gear |34 will rotate at a speedgreater than and in the same direction as the driving gear, thusproducing an overdrive conditionA which is maximum when the controlshaft is stoppedl The amount of overdrive depends on dimensionalrelationship-s between gears |22, |08, |38, |2641 and |2flby and llllaand Ilb. This relationship must be such that when driven gear |38 isstationary and driving gear |08 is,` rotated, the forward control shaft|29 will always rotate in the same direction as the driving gearv |08and at a greater speed than gear ISB. Within the above conditions thereare unlimited combinations possible to obtain the desired overdrive.

If A equals one-half the teeth on gear |03 and if B equals one-half theteeth on gear |22 and ifC equals all the teeth on gear lilla' and if Dequals all the-teeth on gear |24a then equals the revolutions of thedriven shaft for revolutions of thedriving shaft.

In order for the mechanism to operate as desired the product of one-halfthe number of teeth of forward control gear |22 (B) times the number ofteeth on gear llfla or ||0b (C) :must always be less than the product ofone-half the number of teeth on the driving gear |08 (A) times thenumber of teeth on gear |24a or |2411 (D).

If BC is greater than AD then forward control shaft |20 will not rotateat a speed greater than driving gear 4|08 and there will be nooverdrive.

EampZe.-If radius-of gear |8=2 and Aradius of gear |'22=1/2 and diameterof gear ||0a=1 and diameter of gear |2|a=l1/5 Bc gEt-1:1 5/24revolutions of driven shaft for revolutions of driving shaft.

the rotation of the reverse control shaft IIB is retarded, the drivengear |34 begins to rotate in the opposite direction to the driving gear|04, i. e. in reverse direction. The more the reverse control shaft isretarded, thelmore the speed of the driven gear I3@` increases, inreverse direction.

When the rotation of the reverse control shaft is stopped, there is adirect reverse drive condition.

There is no overdrive in reverse because the driving and driven gearsare in mesh with pinions Illa and lllb which in this condition rotateabout stationary axes.Y Hence, the driving and driven gears can onlyrotate at the same speed.

The operations under conditions subsidiary to the three mainconditionsmay 'be' more easily understood after the remainder of theinvention is described. Such subsidiary conditions include (underforward condition) acceleration, deceleration, coasting, pushing whenthe engine is stopped (dead battery) and (under neutral condition)tending to roll down hill when the engine is stopped, with the carfacing up hill or facing down hill.

From the foregoing it will be understood that by limiting the rotationof the forward control shaft |20 and the reverse control shaft HB, thedirection and speed of rotation of the driven shaft |30 can becontrolled. The necessity to provide a means for smoothly andautomatically regulating the speed of rotation of these control shaftswill now also be apparent.

In vthe embodiment of my invention herein illustrated, the retardationof rotation or control of the rotation ofY the control shaft isaccomplished by the use of positive displacement hydraulic pumps, suchas conventional gear pumps. Referring to Fig. 3, the forward controlpump FP has its shaft coupled to the forward control shaft |20,illustrated in Figs. 1 and 2. This coupling may be through gears or itmay be accomplished by mounting the pump gear of the forward controlpump upon the same shaft as the gear |22. In like manneraa reversingpump RP is coupled positively with the reverse control shaft IIB.

A third pump GP, termed for convenience the governor pump, is connecteddirectly to the engine or source of power, the transmission of which itis desired to control. This pump GP may, like the other pumps, be ofconventional gearY form.

I. SELECTION or FORWARD, NEUTRAL 0R REVERSE For the purpose of selectivecontrol of the output and action of the forward and reversing pumps Ihave provided a selctor valve S and a cam unit C.

(i) The cam unit The cam unit is illustrated as comprising a casing fromwhich conduits l0 and l2 go respectively to the inlet side of theforward pump lFP and reversing pump RP. The conduit l2 goes extendsoutside the casing of the cam unit. The

shaft maybe operated by a lever C-2 or in any convenient fashion.Rectilinearly movable pushrods C-3 and C-4 are suitably guided, such asby bearing elements C--5 Within the cam unit. Ball-checks O-I and C 'Iare located respectively in conduits I0 and I2 and one or the other isadapted to seat against ports C-8 and C-S respectively in the casing ofthe cam unit when permitted to do so by the positioning of the push rodC-3 and C- when the cam C-I is-turned into forward or reverse position.The cam C-I has a low point so that when the cam is in forward position,as illustrated in Fig. 3, the push rod 0 3 will be against the low pointand will be retracted. Hence the ball-check C-S may seat in the port 08; but the push rod C-4 will engage the higher periphery of the cam sothat the ball-check C-'I will be pushed from its seat C-9. When the camis rotated to the reverse position, the opposite condition will beattained. When the cam is in neutral position between reverse andforward positions, both of the ballchecks will be maintained off theirseats by reasons of the push rods being both pushed outwardly by theirbeing engaged with the high surface of the cam C-I.

The cam unit C is connected to a iluid reservoir T by a conduit I4. Bymeans of the cam and push rods the only ball allowed to seat itself isthe ball of that pump whose output is being controlled. This allows thepumps FP and RP to rotate backward when the selector valve is in thereverse or neutral or in the forward or neutral positions respectively.

(ii) The selector value The selector valve S may be of suitable form.For convenience of illustration, a rotary valve is illustrated in Fig. 3which has six spaced ports l-B inclusive, in a cylindrical valve housingS-T. The valve ports are or may be approximately of the size and spacingshown in Fig. 3. In the embodiment illustrated the valve cylinder S-Bmay be rocked from the neutral position n to the left into forwardposition f (the position of Fig. 3) or to the right about 45 into thereverse position 1'. There is a passage in the valve cylinder havingthree branches. The three branches communicate with ports I, 2 and 3when the valve is in the neutral position. There is also in the valvecylinder another larger passage which communicates with and connects orjoins the ports 4, 5, 6 in neutral position.

The valve cylinder S- may be operated from outside the housing by anoperating lever S--9. When the lever S-9 is moved into the forwardposition, i. e. about to the left from neutral, the passage will affordcommunication between the ports 4 and 6; and the branches d and l; willcommunicate with the ports I and 2 respectively. Ports 3 and 5 will beclosed by the valve cylinder.

When the lever S-B is moved to the right into the reverse position, thepasage :c will afford communication between the ports 4 and 5; and thebranches b and c will communicate with the ports 3 and I respectively.The ports 2 and 6 will be closed.

The port 4 is connected by a conduit I5 to the reservoir T. The ports 2and are connected by conduits I7, I8 and I9 to the outlet'port of theforward pump FP. The ports 3 and 6 are connected by conduits 2 I, 22 and23 to'a brake cylinder, hereinafter described, which in turn connectswith the outlet of the reversing pump by a conduit 24. The port Iconnects with a regulator 6 valve VR. hereinafter more fully described,by'a conduit'26. j f

From the foregoing itv may be" observed that when the valve'is intheforwardposition the forward pump FP is connected with theregulator Rby means of conduits |18, I9 and 26. Atth'e same time the reversing pumpis connected through the brake B by the conduits 22, 2| and I 5 to thereservoir T.

When the valve is in the reverse positionrthe reversing pump RP isconnected by conduits 22, 23 and 26 to the regulator R while the forwardpump is connected by conduits I8, I1 and I6 to the reservoir T.

In Fig. 4 (in which like reference characters indicate equivalent partsof other figures)V a poppet type selector valve is illustrated. Thistype of valve is suited for use as a selector valve in this inventionbecause it is particularly adapted to meet the following conditions ofoperation. It is important when one of the contro1 shafts is in theprocess of being selected by operation of the selector valve, that theother shaft have complete freedom. It is also importanty that during theselection or manipulation of the valve no restrictive conditions be setup which would override the function of the regulator. Hence there mustbe no interval during which the valve ports are blocked entirely oralmost entirely. VIt is preferable that new connections be establishedfully before: there is a substantial limitation upon and cutting off ofthe previousconnection.

These conditions must be satisedregardless of the type of valveemployed. Within these limits rotary, poppet or other valves in variousforms (of which those` in Figs 3 and 4 are merely examples) may be used.l

In Fig. 4 the poppets m and n are connected together by a connecting barS-I2 pivotally mounted at its midpoint in a partitionrwhich divides thecase into two chambers. There may be a pin and slot or other suitableconnection between the stems of the poppets and the arms of theconnecting bar. The connecting bar may be operated from outside thevalve housing by a lever S-IB equivalent to the lever S-9 in'Fig. 3. Theheads on the poppets control the opening and closing of the ports 2, 3,5 and 6.

II. CONTROL oF SPEED AND POWER To control the speed and powertransmitted I have provided the governor pump GP, a governor G and aregulator R.

(i) The governor pump The governor pump GP has its inlet port GP-Iconnected by a conduit 30 with the reservoir and its outlet port GP--2connected by a conduit 32 to a governor G. The governor pump, beingcoupled with the engine, increases or decreases the flow of fluidthrough the system as the engine speeds up or slows down.

(ii) The governor by a stop member G-5 extending from the casing i? Wallintothe. riempi-movement of' the piston. Leading into the space betweenthe end of the Ypiston right end in YFig. 3) when the piston is restingagainst the stop G-5 and the adjacent end wall is Va port G,-I ll towhich the conduit 32 connects from the governor pump.

In accurately spaced positions along the casing G--Z are two other portsG-I l and G--l2 which are connected by a common conduit 34 to thereservoir T. The port G-l I may be of T shape l with its leg portion soplaced with relation to the stop G-5 that when the piston G-S restsagainst the stop only the leg portion Aof port G-Il will be partly open.Thus, when the engine is idling and the governor pump is rotatingslowly, the

fluid from the pump may pass through the partially open port G-II andreturns to the reservoir through the conduit 36 without affecting theposition of the governor piston.

It will be observed that when the governor pump is speeded up by theacceleration of the engine, the increased uid supply and pressuremovement.

In another wall, for example in the upper wall of the casing G-2, thereis a fourth port G-Iil.

YThe port G--M communicates with the governor as Well as with theregulator R located above the governor as will hereinafter be described.The governor piston, however, controls the communi- If desired;l thecasing 4oftheregulator may be mounted on the casing of the governor. Thepiston R-Z slides within the regulator casingand is normally urged Vtothe left in Figure 3 by a compression spring Rf-d acting upon one sideof the head of the piston R-2. The other end of the spring R-4 may haveits position adjusted to thereby adjust the tension Vof the spring andthe pressure which will have to be overcome for a given movement of thepiston R-Z. The adjustment means maycomprise a screw bolt R-5 threadedthrough a tapped opening in one -end of the casing of the regulator. Anenlarged head R-G may aord a seat for the spring and `maybe attached ifdesired to the end of the lscrew bolt R-5. To limit the movement of thepiston R-Z as it tends to compress the spring R-4 a stop R-l may beprovided extending into 'the ycasing of the regulator in the path ofmovement ofthe piston.

The port G-M between the regulator and the Vgovernor is unrestricted bythe movement of the piston R-2 in any position thereof. In addition tothe port G-i A from the governor into the regrulator, there are otherportsA R-l and R-IZ leading elsewhere. The port R-l communicates throughthe conduit 26 with the selector valve S and is located preferably' -inthe opposite end of the casing from the spring and adjustment screw boltR-E. Thev port R-IZ is located preferably on the opposite side of theregulator casing from the port G-I.4, but it may be located elsewhere.

cation through the port G-lll to the governor.

For this purpose a valve opening G-li is provided in the wall of thegovernor piston. This passage G-l may be of the same size and shape asthe port G-i. When the governor piston is in the idle position, namely,when urged by the spring G-4 against stop G-5 the passage G-I t will bein register fully with the port G-le'.

A valve passage or opening G-l8 in the bottom wall of the governorpiston communicates with the hereinbefore mentioned bottom port G-l2which is approximately twice as large as the valve passage G-l8. Thepassage G-l and the port G--IZ are in vcommunication therefor at alltimes in the embodiment illustrated. It will be understood, however,that the size oi the passage GI8 and the port G-lZ may be varied so longas it allows full and free discharge of all liquid entering within thegovernor piston. Thus, return of such liquid .freely to the lreservoirunder all conditions is permitted.

From the foregoing it may be observed that movement of the governorpiston (as required by the increase in flow of .uid from the governorpump when the engine is speeded up) cuts oil entirely, the flow ofliquid from the regulator R through the governor piston to the reservoirT. It thus makes the regulator elective at all speeds above idlingspeeds.

(iii) The regulator .piston R-2 which is hollow and open at one end.

The port R--l2 has the degree of its opening controlled by a valvepassage R-l4 through the top wall of the piston R-Z. The port R-l2 andthe passage R--lll are or may be the same size. The passage R-I l is ,solocated in the piston R-2 that when the piston R--Z is against the stopR-l the passage R-I will be fully in register with the port R-I2.

When the piston R-Z is in the opposite position, namely, when the springR-ll has fully expanded and moved the piston into the left end of theregulator housing, the port R-I2 will be completely closed because thepassage R-I4 will have passed beyond the port R-IZ and the wall of thepiston will close oi the port R-I2.

From the foregoing it may be observed that when the selector valve S isin the forward position and the governor pump is speeded up by reason ofthe acceleration of the engine, the pressure upon the governor pistonG-S will ca use it to move gradually into a position somewhat asillustrated in Fig. 3. Such movement will completely close the portG-I4. This gradual blocking off of the escape path from the regulatorthrough the governor, allows the regulator to take over gradually andwithout shock. As soon as the engine has reached a speed Yabove idlingthe governor has done its job and does not function again until theengine speed drops down to idling. Then, the governor piston returns toits stop G-E and the regulator becomes ineffective because ow, stillcoming from the selector valve, escapes through the governor ports G-,I4and G-IZ to the reservoir.

The increase in pressure from pump FP by way of the selector valve S andconduit 26 when the engine .speeds up and the governor ports close willcause the piston R-2 to move to the right (in Fig. 3) against thepressure of spring R-d thus causing the port R-I2 to be more fullyopened by reason of the passage R-I4 coming more fully in registertherewith.

As port R|2 is more fully opened less retarding effect is produced onpump FP and shaft whose speed may then increase, resulting' in a greaterspeed ratio of driving to driven shaft. As the load on the enginedecreases the spring R-4 gradually overcomes the pressure of the fluidentering port R-I 0. Thus the piston R--2 is moved by the spring R-lland lessens the size of the passage R-Id. This causes greater backpressure on pump FP and slows down shaft |20 thus creating a smallerspeed ratio of driving to driven shaft.

The fluid from the regulator may return to the reservoir through aconduit 3B connected with the port R-l 2.

It will thus be apparent that by la greater or less acceleration of theengine or a greater or less load imposed, the amount of back pressureagainst the pump will be increased or decreased and thus there will be avaried retarding effect upon the forward control shaft |20.

The port Pt-IZ is of such size and shape (for example of T shape) thatwhen the regulator piston is at the extreme right against its stop theorice is large enough to handle the entire output of the forward pump orthe reversing pump even when they are operating at their maximum speeds.By this means when too great a load is placed on the engine which it isunable to cope with, the regulator piston will advance to the extremeright against its stop. In this condition the car will not move eventhough the engine is running but will function as if it is in neutral.This feature will prevent structural failures when overload conditionsare reached. As soon as the load is decreased sufliciently thecompression spring R-4 will just begin to move the regulator piston tothe left closing the ports R|2 thus putting the transmission inoperation as previously described.

When the selector valve is in the reverse position, the regulator willbe connected with the reversing pump RP by the conduit 2E, the selectorvalve S, the conduit 22, the brake and the conduit 24. Thus the speed ofthe transmission and power passed from the engine to the driven shaftwill be regulated by the same means as was employed in the forwardcontrol.

III. THE BRAKE The brake B is located between the reversing pump RP andthe selector valve S. It may comprise a casing, preferably cylindricalin which slides a piston B-2. At one end of the casing a port B-lconnects with the conduit 24. In the side wall of the casing adjacentthe port B-l is another port B|2 connecting with the conduit 22. Theport B-IZ is preferably in the form of a slot so as to gradually haveits exposed area diminish as the piston B-2 moves toward the end of thecasing (the left end in Fig. 3). The full open area of the port B|2preferably will be approximately equal to the area of the port B-Hl.Connected with the piston is a rod B-5 extending out the opposite end ofthe brake housing (the right end in Fig. 3). In order to limit thestroke of the piston, a stop member B-B is xedly mounted upon the pistonrod B-E within the brake housing. By reason of the limitation of thestroke of the piston, a chamber B-4 is provided in the right end of thebrake housing as viewed in Fig. 3 between the end of the piston and theend wall of the brake housing. Within this chamber are tension springB-l connected with the end wall of the brake housing and also with ananchor pin fiXedly attached to the piston rod B-5. The springs B-'l tendto constantly urge the brake piston and piston rod so as to engage thestop B- against the right end wall of the brake housing. In order toequalize the pressure on each side of the piston B-2, equalizer holes orpassages B-3 are drilled through the piston parallel to its axis.

A handle B--I may be provided on the outer end of the piston rodextending through a slot B--9 in a guide plate B-8. At one end of theslot B-S there may be an offset recess B-|| into which the handle B|4may be moved when it is desired to put the brake in parking position. Bymeans of the handle portion B|4 the equalized brake piston may be movedeasily into any desired position by hand against the tension of springsB-'|. When the brake is in the parking position, or in other words, atthe left end of the slot in the guide plate B-8, the piston B-2 willhave completely closed off the opening of the port B-|2. In otherpositions of the brake between this extreme brake-on position and thebrake-off position as illustrated in Fig. 3, the brake will be partiallyon and will exert a braking force in accordance with its position.

1V. THE BY-PAss VALVE It is desired to have the brake operative onlyunder two conditions: When the selector valve and cam unit are in thereverse position; and, when the car is coasting and the wheels tend todrive the engine. o

For that reason a by-pass valve V is provided between the brake B andthe reversing pump. This valve is open in the neutral and forwardpositions and provides a by-pass in neutral and forward drivingconditions, as will become clear from the following description.

The valve V may comprise a block or housing having an angular passagetherethrough V-2. Moving across this passage is a slide V-S having anopening or passageway V-4 therethrough adapted to register with thepassageway V-2. A compression spring V-5 acts to urge the slide V-3 inposition so that its opening V-4 is in register with the passage V-2.One end of the passage V-2 connects in any appropriate manner with theconduit 24 between the reversing pump and the brake B. The other end ofthe passage is connected in any suitable manner (not shown) to thereservoir T. Thus, opening of the passage V-2 establishes the by-passfrom the reversing pump to the reservoir.

The rod or slide V-3 extends out one end of the block or housing V intoa housing or valve casing V-IZ. This housing may be divided into twoparts with an opening or valve seal V-I4 therebetween upon which mayseat a valve head V-I! affixed upon the end (the left end in Fig. 3) ofthe slide V-S. One chamber (the left chamber in Fig. 3) of the valvehousing V|2 communicates with the forward pump FP and also with theconduit IU from the cam unit. The other chamber of the casing V-I 2communicates by a conduit 42 with the reservoir T. The completeconnection is not shown.

From the foregoing it may be understood thatV when the apparatus is setin the forward position, if the forward control pump starts to rotatebackward (i. e. when the wheels tend to drive the engine on coasting)the ball-check C-6 will seat immediately and the valve head V|| willalso immediately seat on its seat V-l4. Seating of V|| will close theby-pass Valve V automatically. Because the pump is prevent'e'dsfro'mreverse rotation thewheels of the car (i. e. the driven shaft) maintaina coupling with the engine (the driving shaft) and preventsfreewheeling. Also this Vis the only condition in which the brake can beused-to give greater braking yaction to the engine if desired, asexplained below. Y

An arm V-S on the slide V-3 is engageable with a pivoted lever 50. Thelever B and the selector valve lever S9` and the cam lever C2 may .beinterconnected so as to move in unison into Forward, Neutral or Reverseposition by any suitable means, although for convenience of illustrationin the diagrammatic showing of Fig. 3 these three parts are shownseparately. When the lever 50 is in forward or neutral positions armV-'9 has no effect on it. But when the lever is moved to reverse theslide V-3 is moved to the right and the valve head V|| is caused to seaton its seat V-M. Thus the bypass valve is closed.

Whenever Vthe by-pass valve is closed the brake, when actuated, will beoperative to slow down the car. Thus, the brake will be inoperativeexcept during reverse operation of the car or in a coasting conditionwhen the wheels tend to drive the engine. Bearing in mind therelativeactions of the by-pass Valve an'd the brake, the following conditionsmay be noted.

V. OPERATION UNDER CERTAIN CONDITIONS (a) when the selector valves is inthe for ward position and the car is rolling down hill with the wheelstending to drive the engine, the brake B is moved manually by BillY inthe amount desired to restrict or to close off the brake port BIZ. Thatrestricts the operation of the reverse control pump RP (the by-passvalve being already closed). However, when the car slows down to a pointequivalent to engine speed there will no longer be back pressure in theforward control pump FP to keep the valve head V-il on its seat V-Il.Therefore, spring V-5 unseats that valve V|| and opens the by-pass V-2,thereupon making the brake' inoperative or ineffective.

(b) If the car is parked with the selector valve S in reverse positionand the brake B in the parked position the shaft H6 of the reversecontrol pump will beheld stationary by the ball check C-'l and the brakeB. In this condition the car is in direct drive connection with theengine, and will resist rolling forward or backward.

(c) If the car is facing down hill the selector S may be placed inforward position and the brake B in parked position. In this conditionshaft l2() can not rotate in reverse, due to ball check C-; and thereverse control shaft H6 can not rotate forward due to the brake B andley-pass V (valve V will close automatically due to back pressure inFP). In above condition the wheels would be locked against forwardmotion.

VI. GENERAL OPERATION The following is a description of the operation ofthis invention under simple driving conditions when the invention isapplied to a common automobile. The selector lever S-9 is placed inneutral andthe engine is started as in the conventional automobile.Placing of the selector lever S-Q in that position also causes thelevers C--Zl and -50 to move into neutral position since' all three areconnected'and moveas-afunit (the mechanism interconnecting lever S9,cam? unit C2, and lever 50, is not shown in theillust'ration, but may beof any well known systemY of! linkage adapted tothe particularinstallation) With the engine in idling speed the selector lever may be'moved to either forward or reverse position. The engine accelerator isthen depressedand 'the car smoothly ybegins to movel and pickup speed.This; isaccomplished because the governor pump GP, increasing thepressure-in thergovernor G, causes the governor piston G-3 to partiallyor completely close the port G-'|4. ThereuponV the pressure in theregulatorv R is increased by pressure from FP or RP. Such increaseVcauses movement of the pistonR-LZ lagainstthe effortof the spring R-.The pressure is also transmitted back to the forward or reverse pumpde-` pending upon whichposition the vselectorlever has been moved into.Thus the load on one orv the other of those pumps is increased causing aretarding of its rotation and concomitantly the retardation of eitherthe gear E22 or the reverse' control shaft |16. Such retardation causesthe increase in speed of the driven gear through the gearmechanismillustrated in Figs. 1 and 2.

The harder the accelerator is depressed, the greater the disproportionbetween thespeedof the engine and of the driving wheels; or, in terms ofFigs. 1 and 2, the greater the speed difference between gear |108andcgear |38. 'The greater this difference inA speed between gear |108rand gear |38 the greater the speed and torquev resulting in shaft |28lthrough gears Hna, H05, |2401., |241), and |22. This increase in speedand torque of shaft' |20V causes a greater output of pump FP which is`coupled thereto. The increased output of pumpQFPis forced'to furthercompress the compression spring R4 of the regulator R. This increasedload on' the voutput of pump FP produces a braking effect onthe speed ofshaft |20. This braking force on shaft 'I'Zlis transmitted back throughthe .gear tra-in |240.,

|241), lla, Hub, |08 and |38 thus ,producing a compensating increase inIR. P. M. of gear |33 and hence the driven shaft |30. The speed'of'gear|38 increases and gradualiyapproaches thespeed of gear |08 as cruisingconditions are reached. The nearer the speed of gear |38 approaches thespeed of gear |68 the less the torque and speed of shaft 26 and the lessthe output of pump FP. As minimum driving leads are encountered thetorque 4of shaft |21! and hence the output of pump' FP becomes smallenough so that the `extended compression spring R4 moves the piston R2to the extreme left p'ositionthus blocking all Y output of pump'FP. Withpump FP'stoppedthe shaft |20 isVv held stationary; the transmission isthen in its maximum overdrive condition and will remain so until anincrease in engine load again changes the relative speeds of gears |358and |08.

To stop, the accelerator is Vreleased and the car is allowed to slowdownby the inherent'braking action of the idling engine. `It may morerapidly be decelerated by the usual foot brake or'fby the brake embodiedin this invention. A s-previously explained if the brake lever B-5 ismoved against the tension of the springs B-`| to causev the piston B-Zto reduce the area of the port- B-|2, an increase inl pressure will .betransmitted back to the reverse control pump, the forward control pumpbeing prevented from r'everse. rotation under such conditions as previ-lously explained.

As the car slows down to a speed of idling, there is no need to shiftthe selector lever to neutral. It can be left in forward or reverse evenwhen the car is fully stopped. The car will stay at rest on the level aslong as the engine is in idling speed. Depression of the acceleratorwill again start the car in motion.

The car can be shifted from forward to reverse and vice versa regardlessof speed, although it is not intended that such a reversal should takeplace while the car is going at high speed.

Although the invention has been described as applied to the automotiveindustry, it has adaptability elsewhere. The recent trend to Dieselinstallations in railroads has developed need for a stepless mechanicaltransmission. Only in the light Diesel installations has the mechanicaltransmission been practical. In the heavy duty high speed Diesels thestepped mechanical transmission has not been practical because of theinterruption in tractive force during shifting and also due to the hugeclutches which were necessary. As a result the newer Diesels areDiesel-electric units. Thus, the principle of this invention could beused in automotive, railroad, marine and industrial fields, wherever acontinuously variable mechanical transmission is required in which thegears are constantly in mesh.

Many modifications of my invention will occur to those skilled in theart. Therefore I do not limit it to the specific embodiment illustrated.

I claim:

1. In a hydraulic system for controlling a transmission, a forward speedcontrol pump, a reverse speed control pump, a regulator valve forcontrolling the speed of said forward and reverse control pumps, agovernor pump whose output is directly proportional to engine speed, agovernor responsive to changes in output of said governor pump, suchchanges in output when below a predetermined minimum causing theregulator valve to be ineffective, a manually operable selector valvefor selectively directing the output of the forward and reverse controlpumps to the regulator valve.

2. In combination with a system as claimed in claim 1 means toindependently control the speed of the reverse control pump when thetransmission is in a coasting condition in which the driven member ofsaid transmission acts as the driving member.

3. In combination with a system as claimed in claim 1 means to preventreverse rotation of that control pump whose output is not beingcontrolled.

4. A transmission mechanism comprising a driving gear, a driven gear,gear mechanism connecting said driving and driven gears and in meshtherewith at all times, said connecting mechanism including a forwardcontrol shaft carrying a gear which turns therewith, a revolvablereverse control member, gear means rotatably mounted on said member andmeshing continuously with said driving and driven gears and also withthe said forward control gear, retardation of either said forwardcontrol shaft or said reverse control member causing an increase in thespeed of the driven shaft, said increase being in the forward directionif the control shaft be retarded or in the reverse direction if thereverse control member be retarded, in combination with a control systemcomprising forward control means associated with the forward controlshaft, reverse control means associated with the reverse control member,means to regulate the operation of the forward and the reverse controlmeans, means to selectively interconnect said regulating means with oneor the other of said control means, governor means connected with saidregulator and modifying the action thereof in response to changes inspeed of said driving shaft.

5. A transmission mechanism as claimed in claim 4, a governor pump theoutput of which determines at what minimum speed retardation of eitherthe forward control shaft or the reverse control member is possible.

ROBERT H. BAILEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,039,743 Holliday Oct. 1, 19121,338,767 Granzow May 4, 1920 2,181,118 Buiner Nov. 28, 1939 2,278,351Havens Mar. 31, 1942 FOREIGN PATENTS Number Country Date 116,846 GreatBritain June 27, 1918 470,412 France Sept. 10, 1914

